In general, reading about the same subject from a different author is a great way to learn and retain the material better. This is true even if neither author is objectively “better” than the other. Something about recognizing the same underlying concept expressed in different words helps to fix that concept in the mind.

It’s possible to exploit this phenomenon even when you have only one text to work with. One trick I use when working through a math text is to willfully use different notation in my notes next to the text. Using a different notation forces me to make sure that I’m really following the details of the argument. Expressing the same logic in different symbols makes it easier to see through those symbols to the underlying logic.

I very strongly recommend tackling an area of logic (or indeed any new area of mathematics) by reading a series of books which overlap in level (with the next one covering some of the same ground and then pushing on from the previous one), rather than trying to proceed by big leaps.

In fact, I probably can’t stress this advice too much, which is why I am highlighting it here. For this approach will really help to reinforce and deepen understanding as you re-encounter the same material from different angles, with different emphases.

In general, reading about the same subject from a different author is a great way to learn and retain the material better. This is true even if neither author is objectively “better” than the other. Something about recognizing the same underlying concept expressed in different words helps to fix that concept in the mind.

It’s possible to exploit this phenomenon even when you have only one text to work with. One trick I use when working through a math text is to willfully use different notation in my notes next to the text. Using a different notation forces me to make sure that I’m really following the details of the argument. Expressing the same logic in different symbols makes it easier to see through those symbols to the underlying logic.

The author of the Teach Yourself Logic study guide agrees with you about reading multiple sources: